Data communication control device with peripheral device
Loss of data to be transmitted from a peripheral device to a host before a software hierarchy of the host side completely starts is prevented. In a time period before a host completely reached a normal operation mode from a sleep mode, data outputted from a receiver is stored in second buffer memory of a communication control device. When the host reaches the normal operation mode, an application hierarchy in the host transmits a transmission approval command to a control unit, and then the data is transferred from the second buffer memory to first buffer memory. Since communication between the host and the communication control device of the receiver is resumed and then the data stored in the first buffer memory is sent to the host through a USB line, loss of the data can be prevented.
1. A communication control device that controls data communication between a host computer and a peripheral device, comprising:
first buffer memory that stores data to be sent to the host computer;
second buffer memory that stores data outputted from the peripheral device; and
a control unit that is operable to generate a resume signal that is output from the peripheral device to the host, which is operable to generate a transmission approval command that is transferred to the peripheral device,
wherein the control unit is operable to transfer the data stored in the second buffer memory to the first buffer memory after receiving the transmission approval command from the host approving data transmission from the peripheral device to the host computer,
wherein the control unit is operable to transmit data from the first buffer memory to the host computer only after the transmission approval command is received from the host in response to the resume signal,
wherein the first buffer memory and the second buffer memory are FIFO buffers.
2. The communication control device according to claim 1 , wherein the second buffer memory is a multi-stage FIFO buffer.
3. The communication control device according to claim 1 , wherein the data communication is performed using a USB line.
4. The communication control device according to claim 1 , wherein the peripheral device includes the first buffer memory and the second buffer memory.